While people have criticized that OpenID’s have security weaknesses and may be vulnerable to phishing attacks, more and more sites are starting to use them. Case in point… Yahoo! Yahoo just announced support for OpenID which is huge. In case you’re not familiar with it, OpenID is a decentralized single sign-on system meaning with one OpenID, you can sign into multiple sites. This system is great for those of us who get sick of creating a new account for every site that we use on the web. Remembering multiple usernames and passwords can get tedious, and OpenID solves these issues.

According to Yahoo’s announcement, this new option will be available in public beta starting on January 30th – less than two weeks away. The fact that Yahoo joined on is huge – doing so tripled the number of OpenID accounts to 368 million! It’s clear that the project is gaining popularity all around which is great because the more people that use it, the better chance it has of becoming mainstream. Aside from Yahoo, other major sites like America Online, Orange, Live Journal, Zoomr, and others have already joined in on the project. In all, it’s estimated that there are more than 9,000 OpenID compliant sites.

From the sounds of it, Yahoo intends to get involved more deeply with the OpenID project. Speaking to Michael Arrington of TechCrunch, Raj Patel, Yahoo’s director of membership and registration said, “This is just the first step in working with OpenID.” Arrington said that Patel would not confirm if Yahoo would end up becoming a “relying party” which means that users with third party OpenIDs could log into Yahoo. All that was said was that Yahoo’s goal was to move in that direction.

Yahoo conveniently has a page setup where you can learn more about OpenID and take a tour. Check that out here.